Improved plunger for glass-molds



llltited @Sintra JOHN MCCORD, OF EAST BIRMINGHAM, PENNSYLVANIA, ASSIGNOR TO HIMSELF AND JOHN BRYOE, OF SAME PLACE.

Letters Patent No. 101,485, dated April 5, 1870.

The Schedule referred to in these Letters Patent and making vparl: of the same.

To all whom 'it may concern: y

Be it known that I, JOHN McCoRn, of East Birmingham, in the county of Allegheny and State of Pennsylvania, have invented-a new and useful Improvement in Glass-Mold Plnnger; and I do hereby declare the following to be a full, clear, and exact descriptiou thereof, reference being had to the accompanying drawing making a part of this specification, in which- Figure 1 is a side elevation of my improved plunger, and

Figure 2, by a sectional elevation, illustrates the construction thereof. v

Like letters of reference indicate like parts in each.

In the manufacture of hollow articles of pressed glass-ware a metal plunger is required in order to form the inside or hollow part of the article.

To keep such plungers from becoming overheated they have been cast hollow and fitted with waterpipes so as to keep up a supply of cold water in the hollow chamber or cavity.

I have found that plungcrs so constructed frequently crack, especially at or near `the lower end, in consequence of the unequal expansion and contraction caused by cold water inside the plunger, and melted glass outside,l the plunger cracking the more readily as it is commonly made of"cast metal. They are then spoiled for use, and, as they are fitted up with water-pipe connections at a considerable cost, the loss thereby occasioned to glass manufacturers is considerable.

My improvement -relates to the construction of such plungers.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construe.- tion and manner of use.

' The -water-chamber a I make in any desirable way, one way being to take a piece of gas-pipe of the desired length, and close each end by an iron cap or disk.

In any part or parts of the chamber so made I make two holes into which I insert, by a screw-joint or otherwise, two pipes, one, b, for Ithe inflow, and the other, b', for the out-flow of water.

These'pipes, b b', extend upward or outward, or both, far enough to leave the-body of the plunger above its pressing surface, and are connected when in use with suitable water-supplying and discharging devices.

The water-chamber a and pipes b b' so made, I then insert in the cavity of the mold in body c of the plunger isv to be cast. vThe casting is then done in the usual way, and the plunger is produced ready for use, as soon as the connections of the pipes b b' with the desired water-supplying and discharging devices are made.

By this construction I can make plungers at about one-fourth the cost ofthe hollow plungers heretofore in use.

Also, by having a wrought-iron chamber a, I almost wholly avoid the liability of the plunger to crack under the. unequal expansion and contraction occaf sioned by the introduction of water, since the wrought iron possesses greater` tenacity than the cast-iron.

The relative size of' chamber and plunger may be varied at pleasure, and other metalsv than iron be ein ployed, if so desired, and other kinds of iron than wrought iron.

What I claim as my invention, and desire to secure by Letters Patent, is

l. A hollow cast-metal glass-mold plunger, the cavity of which has a wrought-metal lining, substantially as described.

2. The manufacture of glass-mold plungers by first preparing a hollow water-chamber'and then casting the body of the plunger onto and around the chamber, substantially as described.

1n testimony whereof,I, the said J OHN MCOORD,

have hereunto set my hand.

v JOHN MGOORD.

Witnesses t AUGUST AMMON, C. J. Scnurfrz.

which the 

